The present invention relates to a deflection unit (yoke) for a cathode-ray tube, which is arranged toroidally around the neck of the tube and opens up in a trumpet-like manner towards the screen, and produces an electro-magnetic field for deflecting one or more electron beams, and in which, at least in one direction of displacement, the deflecting field is produced by a set of saddle-type coils, the windings of which are wound on to a coil form on the face sides and on the inner surface of the deflection unit.
With respect to deflection units, it is a general requirement to achieve the necessary field pattern by way of the physical configuration of the deflection coils.
The required accuracy of the field pattern to be formed is particularly high in the case of deflection units which, owing to the shape of the picture tube, open up in a trumpet-like manner, especially in the case of color television picture tubes having high deflection angles.
Such high requirements can be met approximately by employing, for example, toroidal coils.
In the case of saddle-type coils having the advantage of a higher sensitivity over the toroidal coils, this has far less been able to achieve up to now owing to the more difficult geometry and for reasons of the difficulties in manufacture resulting therefrom, especially when a high impedance and, consequently, a large number of turns is required for circuit-technical reasons.
From the German Published Patent Application (DT-OS) Nos. 26 01 205 and 26 30 297, a deflection unit with saddle-type coils has become known, the windings of which are guided on the face sides of the yoke in grooves, with a possibility of providing further points of support on the inside surface of the yoke.
A similar point-wise fixing of the winding turns is also found in an example of embodiment relating to a deflection unit with saddle-type coils as disclosed in the German Printed Patent Application (DT-AS) No. 26 15 126. The guiding of the winding turns on the inside of the yoke by way of axial grooves in the core material is disclosed in the German Petty Patent (DT-GM) No. 74 41 864.